Your eyes allow you to navigate the surrounding world. From perceiving an image through your eyes and translating it in the brain, these vital organs have powerful functions that dictate every moment of the waking day. They guide where you go, recognize who you see and keep you safe by alerting danger. Unfortunately, diseases brewing inside the eyes often do not present symptoms to alert you, and, though some can be cured, others can lead to blindness.
Conjunctivitis
More commonly known as "pink eye," conjunctivitis is an inflammation of the conjunctiva--the membrane-covering whites of the eyes and the lining of the interior of the eyelids. Conjunctivitis is caused by either a bacterial or viral infection and is highly contagious. Bacterial conjunctivitis affects both eyes and presents redness, heavy discharge and crusting on the eyelids. Viral conjunctivitis usually affects one eye, which appears red, with a light discharge and excessive tearing. Crusting on the eyelids may sometimes occur. Pink eye is spread by respiratory droplets from coughing and sneezing of an affected individual. Touching unwashed hands, unsanitary surfaces or sharing towels and linens spreads the infection. Children are most frequently affected by conjunctivitis, notes AllAboutVision.com.
Cataracts
An opaque cloudiness of the lens caused by a lumping of proteins is called cataracts. This eye condition results in distortion of projected images, causing blurry vision and gradually progressing to blindness. According to the National Eye Institute (NEI), other causes of cataracts development include smoking, using steroids and diabetes. Most cases of cataracts relate to aging, but the disease can also be inherited or developed after eye surgery, eye injury or exposure to radiation.
Glaucoma
Several types of ocular diseases fall under the term glaucoma. They all result from an increased pressure of fluid inside the eye, causing damage to the optic nerve and eventually progressing to blindness. Glaucoma does not provide warning symptoms and increased intraocular pressure can go unnoticed, with optic nerve damage having already happened. Initially, side vision, or peripheral vision, is affected, followed by loss of central vision over time. The Glaucoma Research Foundation states that glaucoma is incurable, but medical treatment can slow down the progress of the disease.
Macular Degeneration
The NEI explains that macular degeneration, or AMD (age-related macular degeneration), is the leading cause of blindness in people over 60 years of age. The macula of the eye allows us to see fine detail in central vision, and, when it degenerates, vision becomes increasingly blurry. Two types of AMD exist: wet and dry. Wet AMD progresses rapidly, and seeing straight lines as wavy is the earliest sign. Dry AMD progresses through three stages over a slower period of time and causes a big, blurry dark spot in the middle of central vision. The NEI also states AMD has no cure, but medical treatments can help slow progression.
Diabetic Retinopathy
The American Academy of Ophthalmology calls diabetes the leading cause of new blindness in the United States. Diabetic retinopathy has become common, because over 24 million people have diabetes, and people with the disease are 25 times more likely to become blind. Blood vessel changes in the eye result in two types of diabetic retinopathy: nonproliferative (NPDR) and proliferative (PDR).
NPDR is characterized by blood vessel leakage in the eye, including leaking of cholesterol and fats. This produces microaneurysms (tiny bulgings of blood vessels), spots of blood on the retina and hard deposits formed from cholesterol and fat. Blindness results from NPDR, due to both swelling of the macula and lack of circulation to the macula.
PDR is characterized by growth of new abnormal blood vessels after old ones have closed off. Severe vision loss, including both central and peripheral, results from the new vessels bleeding into the eye and the increased eye pressure from this leakage. Also, scar tissue from the new vessel formation can pull and detach the retina from the eye wall. Prevention by strict control of blood sugar levels will best prevent both types of AMD and reduce the long-term risks of blindness.
